/* vi: set sw=4 ts=4: */
/*
- * Utility routines.
+ * Stub for linking busybox binary against libbusybox.
*
- * Copyright (C) tons of folks. Tracking down who wrote what
- * isn't something I'm going to worry about... If you wrote something
- * here, please feel free to acknowledge your work.
+ * Copyright (C) 2007 Denys Vlasenko <vda.linux@googlemail.com>
*
- * Based in part on code from sash, Copyright (c) 1999 by David I. Bell
- * Permission has been granted to redistribute this code under the GPL.
- *
- * Licensed under GPLv2 or later, see file License in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
*/
-
-#include <assert.h>
#include "busybox.h"
-#define PROTOTYPES
-#include "applets.h"
-#undef PROTOTYPES
-
-
-/* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
-#if ENABLE_STATIC && defined(__GLIBC__) && !defined(__UCLIBC__)
-#warning Static linking against glibc produces buggy executables
-#warning (glibc does not cope well with ld --gc-sections).
-#warning See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
-#warning Note that glibc is unsuitable for static linking anyway.
-#warning If you still want to do it, remove -Wl,--gc-sections
-#warning from top-level Makefile and remove this warning.
-#endif
-
-#if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
-static const char usage_messages[] =
-#define MAKE_USAGE
-#include "usage.h"
-#include "applets.h"
-;
-#undef MAKE_USAGE
-#else
-#define usage_messages 0
-#endif /* ENABLE_SHOW_USAGE */
-
-#undef APPLET
-#undef APPLET_NOUSAGE
-#undef PROTOTYPES
-#include "applets.h"
-
-static struct BB_applet *applet_using;
-
-/* The -1 arises because of the {0,NULL,0,-1} entry above. */
-const unsigned short NUM_APPLETS = (sizeof (applets) / sizeof (struct BB_applet) - 1);
-
-
-#ifdef CONFIG_FEATURE_SUID_CONFIG
-
-#include <ctype.h>
-
-#define CONFIG_FILE "/etc/busybox.conf"
-
-/* applets [] is const, so we have to define this "override" structure */
-static struct BB_suid_config
-{
- struct BB_applet *m_applet;
-
- uid_t m_uid;
- gid_t m_gid;
- mode_t m_mode;
-
- struct BB_suid_config *m_next;
-} *suid_config;
-
-static int suid_cfg_readable;
-
-/* check if u is member of group g */
-static int ingroup(uid_t u, gid_t g)
-{
- struct group *grp = getgrgid(g);
-
- if (grp) {
- char **mem;
-
- for (mem = grp->gr_mem; *mem; mem++) {
- struct passwd *pwd = getpwnam(*mem);
-
- if (pwd && (pwd->pw_uid == u))
- return 1;
- }
- }
- return 0;
-}
-
-/* This should probably be a libbb routine. In that case,
- * I'd probably rename it to something like bb_trimmed_slice.
- */
-static char *get_trimmed_slice(char *s, char *e)
-{
- /* First, consider the value at e to be nul and back up until we
- * reach a non-space char. Set the char after that (possibly at
- * the original e) to nul. */
- while (e-- > s) {
- if (!isspace(*e)) {
- break;
- }
- }
- e[1] = 0;
-
- /* Next, advance past all leading space and return a ptr to the
- * first non-space char; possibly the terminating nul. */
- return skip_whitespace(s);
-}
-
-
-#define parse_error(x) do { errmsg = x; goto pe_label; } while(0)
-
-/* Don't depend on the tools to combine strings. */
-static const char config_file[] = CONFIG_FILE;
-
-/* There are 4 chars + 1 nul for each of user/group/other. */
-static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";
-
-/* We don't supply a value for the nul, so an index adjustment is
- * necessary below. Also, we use unsigned short here to save some
- * space even though these are really mode_t values. */
-static const unsigned short mode_mask[] = {
- /* SST sst xxx --- */
- S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */
- S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */
- 0, S_IXOTH, S_IXOTH, 0 /* other */
-};
-
-static void parse_config_file(void)
+#if ENABLE_BUILD_LIBBUSYBOX
+int main(int argc UNUSED_PARAM, char **argv)
{
- struct BB_suid_config *sct_head;
- struct BB_suid_config *sct;
- struct BB_applet *applet;
- FILE *f;
- const char *errmsg;
- char *s;
- char *e;
- int i, lc, section;
- char buffer[256];
- struct stat st;
-
- assert(!suid_config); /* Should be set to NULL by bss init. */
-
- if ((stat(config_file, &st) != 0) /* No config file? */
- || !S_ISREG(st.st_mode) /* Not a regular file? */
- || (st.st_uid != 0) /* Not owned by root? */
- || (st.st_mode & (S_IWGRP | S_IWOTH)) /* Writable by non-root? */
- || !(f = fopen(config_file, "r")) /* Cannot open? */
- ) {
- return;
- }
-
- suid_cfg_readable = 1;
- sct_head = NULL;
- section = lc = 0;
-
- do {
- s = buffer;
-
- if (!fgets(s, sizeof(buffer), f)) { /* Are we done? */
- if (ferror(f)) { /* Make sure it wasn't a read error. */
- parse_error("reading");
- }
- fclose(f);
- suid_config = sct_head; /* Success, so set the pointer. */
- return;
- }
-
- lc++; /* Got a (partial) line. */
-
- /* If a line is too long for our buffer, we consider it an error.
- * The following test does mistreat one corner case though.
- * If the final line of the file does not end with a newline and
- * yet exactly fills the buffer, it will be treated as too long
- * even though there isn't really a problem. But it isn't really
- * worth adding code to deal with such an unlikely situation, and
- * we do err on the side of caution. Besides, the line would be
- * too long if it did end with a newline. */
- if (!strchr(s, '\n') && !feof(f)) {
- parse_error("line too long");
- }
-
- /* Trim leading and trailing whitespace, ignoring comments, and
- * check if the resulting string is empty. */
- if (!*(s = get_trimmed_slice(s, strchrnul(s, '#')))) {
- continue;
- }
-
- /* Check for a section header. */
-
- if (*s == '[') {
- /* Unlike the old code, we ignore leading and trailing
- * whitespace for the section name. We also require that
- * there are no stray characters after the closing bracket. */
- if (!(e = strchr(s, ']')) /* Missing right bracket? */
- || e[1] /* Trailing characters? */
- || !*(s = get_trimmed_slice(s+1, e)) /* Missing name? */
- ) {
- parse_error("section header");
- }
- /* Right now we only have one section so just check it.
- * If more sections are added in the future, please don't
- * resort to cascading ifs with multiple strcasecmp calls.
- * That kind of bloated code is all too common. A loop
- * and a string table would be a better choice unless the
- * number of sections is very small. */
- if (strcasecmp(s, "SUID") == 0) {
- section = 1;
- continue;
- }
- section = -1; /* Unknown section so set to skip. */
- continue;
- }
-
- /* Process sections. */
-
- if (section == 1) { /* SUID */
- /* Since we trimmed leading and trailing space above, we're
- * now looking for strings of the form
- * <key>[::space::]*=[::space::]*<value>
- * where both key and value could contain inner whitespace. */
-
- /* First get the key (an applet name in our case). */
- if (!!(e = strchr(s, '='))) {
- s = get_trimmed_slice(s, e);
- }
- if (!e || !*s) { /* Missing '=' or empty key. */
- parse_error("keyword");
- }
-
- /* Ok, we have an applet name. Process the rhs if this
- * applet is currently built in and ignore it otherwise.
- * Note: This can hide config file bugs which only pop
- * up when the busybox configuration is changed. */
- if ((applet = find_applet_by_name(s))) {
- /* Note: We currently don't check for duplicates!
- * The last config line for each applet will be the
- * one used since we insert at the head of the list.
- * I suppose this could be considered a feature. */
- sct = xmalloc(sizeof(struct BB_suid_config));
- sct->m_applet = applet;
- sct->m_mode = 0;
- sct->m_next = sct_head;
- sct_head = sct;
-
- /* Get the specified mode. */
-
- e = skip_whitespace(e+1);
-
- for (i=0 ; i < 3 ; i++) {
- const char *q;
- if (!*(q = strchrnul(mode_chars + 5*i, *e++))) {
- parse_error("mode");
- }
- /* Adjust by -i to account for nul. */
- sct->m_mode |= mode_mask[(q - mode_chars) - i];
- }
-
- /* Now get the the user/group info. */
-
- s = skip_whitespace(e);
-
- /* Note: We require whitespace between the mode and the
- * user/group info. */
- if ((s == e) || !(e = strchr(s, '.'))) {
- parse_error("<uid>.<gid>");
- }
- *e++ = 0;
-
- /* We can't use get_ug_id here since it would exit()
- * if a uid or gid was not found. Oh well... */
- {
- char *e2;
-
- sct->m_uid = strtoul(s, &e2, 10);
- if (*e2 || (s == e2)) {
- struct passwd *pwd = getpwnam(s);
- if (!pwd) {
- parse_error("user");
- }
- sct->m_uid = pwd->pw_uid;
- }
-
- sct->m_gid = strtoul(e, &e2, 10);
- if (*e2 || (e == e2)) {
- struct group *grp;
- if (!(grp = getgrnam(e))) {
- parse_error("group");
- }
- sct->m_gid = grp->gr_gid;
- }
- }
- }
- continue;
- }
-
- /* Unknown sections are ignored. */
-
- /* Encountering configuration lines prior to seeing a
- * section header is treated as an error. This is how
- * the old code worked, but it may not be desirable.
- * We may want to simply ignore such lines in case they
- * are used in some future version of busybox. */
- if (!section) {
- parse_error("keyword outside section");
- }
-
- } while (1);
-
- pe_label:
- fprintf(stderr, "Parse error in %s, line %d: %s\n",
- config_file, lc, errmsg);
-
- fclose(f);
- /* Release any allocated memory before returning. */
- while (sct_head) {
- sct = sct_head->m_next;
- free(sct_head);
- sct_head = sct;
- }
+ return lbb_main(argv);
}
-
-#else
-#define parse_config_file() ((void)0)
-#endif /* CONFIG_FEATURE_SUID_CONFIG */
-
-#ifdef CONFIG_FEATURE_SUID
-static void check_suid(struct BB_applet *applet)
-{
- uid_t ruid = getuid(); /* real [ug]id */
- uid_t rgid = getgid();
-
-#ifdef CONFIG_FEATURE_SUID_CONFIG
- if (suid_cfg_readable) {
- struct BB_suid_config *sct;
-
- for (sct = suid_config; sct; sct = sct->m_next) {
- if (sct->m_applet == applet)
- break;
- }
- if (sct) {
- mode_t m = sct->m_mode;
-
- if (sct->m_uid == ruid)
- /* same uid */
- m >>= 6;
- else if ((sct->m_gid == rgid) || ingroup(ruid, sct->m_gid))
- /* same group / in group */
- m >>= 3;
-
- if (!(m & S_IXOTH)) /* is x bit not set ? */
- bb_error_msg_and_die("you have no permission to run this applet!");
-
- if (sct->m_gid != 0) {
- /* _both_ have to be set for sgid */
- if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
- xsetgid(sct->m_gid);
- } else xsetgid(rgid); /* no sgid -> drop */
- }
- if (sct->m_uid != 0) {
- if (sct->m_mode & S_ISUID) xsetuid(sct->m_uid);
- else xsetuid(ruid); /* no suid -> drop */
- }
- } else {
- /* default: drop all privileges */
- xsetgid(rgid);
- xsetuid(ruid);
- }
- return;
- } else {
-#ifndef CONFIG_FEATURE_SUID_CONFIG_QUIET
- static int onetime = 0;
-
- if (!onetime) {
- onetime = 1;
- fprintf(stderr, "Using fallback suid method\n");
- }
#endif
- }
-#endif
-
- if (applet->need_suid == _BB_SUID_ALWAYS) {
- if (geteuid()) bb_error_msg_and_die("applet requires root privileges!");
- } else if (applet->need_suid == _BB_SUID_NEVER) {
- xsetgid(rgid); /* drop all privileges */
- xsetuid(ruid);
- }
-}
-#else
-#define check_suid(x)
-#endif /* CONFIG_FEATURE_SUID */
-
-
-
-#ifdef CONFIG_FEATURE_COMPRESS_USAGE
-
-#include "usage_compressed.h"
-#include "unarchive.h"
-
-static const char *unpack_usage_messages(void)
-{
- int input[2], output[2], pid;
- char *buf;
-
- if(pipe(input) < 0 || pipe(output) < 0)
- exit(1);
-
- pid = fork();
- switch (pid) {
- case -1: /* error */
- exit(1);
- case 0: /* child */
- close(input[1]);
- close(output[0]);
- uncompressStream(input[0], output[1]);
- exit(0);
- }
- /* parent */
-
- close(input[0]);
- close(output[1]);
- pid = fork();
- switch (pid) {
- case -1: /* error */
- exit(1);
- case 0: /* child */
- full_write(input[1], packed_usage, sizeof(packed_usage));
- exit(0);
- }
- /* parent */
- close(input[1]);
-
- buf = xmalloc(SIZEOF_usage_messages);
- full_read(output[0], buf, SIZEOF_usage_messages);
- return buf;
-}
-
-#else
-#define unpack_usage_messages() usage_messages
-#endif /* ENABLE_FEATURE_COMPRESS_USAGE */
-
-void bb_show_usage(void)
-{
- if (ENABLE_SHOW_USAGE) {
- const char *format_string;
- const char *usage_string = unpack_usage_messages();
- int i;
-
- for (i = applet_using - applets; i > 0;)
- if (!*usage_string++) --i;
-
- format_string = "%s\n\nUsage: %s %s\n\n";
- if (*usage_string == '\b')
- format_string = "%s\n\nNo help available.\n\n";
- fprintf(stderr, format_string, bb_msg_full_version,
- applet_using->name, usage_string);
- }
-
- exit(xfunc_error_retval);
-}
-
-static int applet_name_compare(const void *name, const void *vapplet)
-{
- const struct BB_applet *applet = vapplet;
-
- return strcmp(name, applet->name);
-}
-
-struct BB_applet *find_applet_by_name(const char *name)
-{
- return bsearch(name, applets, NUM_APPLETS, sizeof(struct BB_applet),
- applet_name_compare);
-}
-
-void run_applet_by_name(const char *name, int argc, char **argv)
-{
- if (ENABLE_FEATURE_SUID_CONFIG)
- parse_config_file();
-
- if (!strncmp(name, "busybox", 7))
- exit(busybox_main(argc, argv));
- /* Do a binary search to find the applet entry given the name. */
- applet_using = find_applet_by_name(name);
- if (applet_using) {
- applet_name = applet_using->name;
- if (argc == 2 && !strcmp(argv[1], "--help"))
- bb_show_usage();
- if (ENABLE_FEATURE_SUID)
- check_suid(applet_using);
- exit(applet_using->main(argc, argv));
- }
-}
projects / oweals / busybox.git / blobdiff